This invention relates to the field of electrical connectors made with conductive polymer material.
Elastomeric Conductive Polymer Interconnect (ECPI) is a composite of conductive metal particles in an elastomeric matrix that is constructed such that it conducts along one axis only. In general, this type of material is made to conduct through its thickness. ECPI is generally produced by mixing magnetic particles with a liquid resin, forming the mix into a continuous sheet, and curing the sheet in the presence of a magnetic field. This results in the particles forming columns through the sheet thickness. These columns are electrically conductive, creating anisotropic conductivity. The sheets are subsequently cut to the desired shape and attached to a frame or connector structure by mechanical means, or by the application of adhesive. In some cases, the cut ECPI is simply placed inside the interconnect structure. These methods of ECPI use result in material waste, require assembly labor, and can provide less than optimum performance.
As an illustrative example, consider the prior art assembly method for a surface mounted LGA or BGA connector. The connector consists of an alignment frame and a piece of ECPI material. The ECPI may be attached to the alignment frame either by mechanical means or by an adhesive. In some applications the ECPI can be placed loosely on a printed circuit board, and compressed in place between the device and the board. This is acceptable in some applications such as burn-in and test, but not for most OEM applications.
It is therefore an object of this invention to provide an interconnection component with an integral ECPI.
It is a further object of this invention to provide such a component that minimizes ECPI material waste.
It is a further object of this invention to provide such a component that requires less assembly labor.
It is a further object of this invention to provide such a component that enhances the interconnected performance of the ECPI.
This invention features an interconnection component with integral conductive elastomeric sheet material, comprising a connector frame, and an elastomeric conductive polymer interface (ECPI) integrally coupled to the connector frame. The integral coupling may be enhanced with one or more openings in the frame, in which the ECPI is held. The frame may be annular, and the openings along at least two opposed sides of the frame. The frame may be generally rectangular and the openings along all four sides of the frame.
The interconnection component may further comprise one or more protrusions in the ECPI, and in contact with the frame, to help to maintain registration between the interconnection component and the connected device. The ECPI may be in tension in the frame. The conductive columns in the ECPI may protrude from at least one surface of the ECPI. The ECPI may define one or more depressions proximate at least some of the conductive columns. The interconnection component may further comprise one or more spacer members between one or more portions of the frame, and the ECPI.
The interconnection component may further comprise a flex circuit interconnect in electrical contact with the ECPI, to enhance interconnection of a device to the ECPI. The interconnection component may still further comprise a series of electrical interconnects on the ECPI surface and in electrical contact with the conductive columns.
This invention also features a method of forming an interconnection component with integral conductive elastomeric sheet material, comprising providing a connector frame, casting uncured elastomeric conductive polymer interface (ECPI) material onto the connector frame, and curing the ECPI, to integrally couple the ECPI to the connector frame.
The method may further comprise providing a casting plate defining an annular cavity with a central pedestal, and placing the frame into the cavity before casting the uncured ECPI. The method may still further comprise providing one or more openings in the frame, in which the ECPI is held. The conductive columns in the ECPI may protrude from at least one surface of the ECPI. The protrusion may be created with a material that is liquid at the ECPI casting temperature, and placed between the pedestal and the uncured ECPI.
The method may still further comprise providing an array of high permeability zones in the central pedestal to focus the magnetic field such that the columns of particles are preferentially positioned in the area of the electrical interconnection.